A330578 a(n) is the remainder when the sum of the first n composite numbers is divided by the n-th composite number.

0, 4, 2, 0, 7, 1, 7, 3, 14, 4, 12, 6, 21, 7, 24, 16, 7, 25, 5, 15, 4, 26, 14, 1, 11, 36, 22, 34, 4, 33, 17, 31, 14, 46, 28, 9, 23, 3, 38, 17, 53, 9, 25, 2, 42, 18, 59, 9, 52, 26, 44, 64, 37, 9, 57, 28, 48, 18, 69, 7, 60, 28, 82, 49, 71, 37, 2, 59, 23, 81, 44

Offset: 1

Author

Rémy Sigrist, Dec 18 2019

Keywords

• nonn

Examples

			a(3) = (4 + 6 + 8) mod 8 = 2.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002808, A053767, A071089 (prime variant), A330579 (positions of zeros).

Programs

PARI

s=0; forcomposite (c=4, 96, s+=c; print1 (s%c", "))

Formula

a(n) = A053767(n) mod A002808(n).